Formation and characterization of (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine)/(1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine) supported lipid bilayers on polyelectrolyte multilayer films

Abstract

The report focuses on understanding of the mechanism of formation of supported lipid bilayers (SLBs) by vesicle adsorption and rupture on polyelectrolyte multilayer (PEM) films. The PEM films were constructed by sequential adsorption of positively-poly-l-lysine (PLL) and negatively-poly-l-glutamic acid sodium salt (PGA) charged polyelectrolytes (PEs) on charged surface. The adsorption kinetics of small unilamellar vesicles, prepared from mixtures of phospholipids, zwitterionic unsaturated (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, POPC) and negatively charged unsaturated (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (sodium salt), POPS) was investigated on such PEM polymer cushions, using quartz crystal microbalance with dissipation monitoring (QCM-D). Complementary AFM measurements were performed to verify the morphology of lipid vesicles and isolated bilayer patches on the PEM cushion terminated with positively charged PLL. Properties of solid substrates were characterized with QCM-D and ellipsometry to find information on the layer thickness and water content of these layers. The results suggested that, depending on the number of layers, two pathways of vesicle adsorption may be proposed. We believe that modification of solid surfaces using SLBs is very important for the development of new multifunctional materials for biotechnological applications as cell–membrane models and biosensors and for drug delivery systems.